Shortwave diathermy (SWD) is a therapeutic method that uses high-frequency alternating currents to generate heat within the body’s tissues. This process aims to produce deep heating in areas such as joints and soft tissues.
How Shortwave Diathermy Works
Shortwave diathermy generates heat within the body through the interaction of high-frequency electromagnetic energy with body tissues. This energy causes ions within the tissues to move in various directions, creating friction that increases tissue temperature. The frequency of electromagnetic waves used in SWD typically ranges between 10 and 100 MHz, with 27.12 MHz being a commonly utilized frequency.
There are two primary methods for applying SWD: capacitive and inductive. The capacitive method involves placing electrodes on either side of the body part to be treated, creating an electric field that generates heat. The inductive method uses coils, often in the form of cables or drums, to produce a magnetic field that induces eddy currents within the tissues, leading to heat generation. Heat depth and distribution depend on current strength, tissue type, and application method.
Therapeutic Applications of Shortwave Diathermy
Shortwave diathermy is traditionally employed to address a range of musculoskeletal conditions and symptoms. Its therapeutic effects include reducing pain and inflammation, improving joint range of motion, and decreasing muscle spasms and stiffness.
SWD also promotes healing by increasing local blood flow, which supports cellular regeneration and accelerates recovery for injuries like sprains, strains, and tendinitis. Conditions such as arthritis, bursitis, tenosynovitis, frozen shoulder, and lower back pain are among those for which SWD has been traditionally applied.
Why Its Use is Restricted
The application of shortwave diathermy is subject to significant restrictions due to potential risks and contraindications. Electromagnetic waves generated by SWD can disrupt implanted medical devices such as pacemakers, neurostimulators, and defibrillators, potentially causing device damage or posing a risk to the patient. Patients with metal implants or intrauterine devices may experience increased temperatures around the implant site, which could lead to burns.
Pregnancy is an explicit contraindication for SWD use. Research indicates an association between exposure to shortwave diathermy during conception and an increased incidence of miscarriage and low birth weight. Therefore, SWD should not be applied to pregnant women, regardless of the body area.
SWD is also avoided in patients with certain types of cancer, as the heat generated could potentially exacerbate malignant conditions.
Other conditions that contraindicate SWD use include:
Severe or excessive edema
Acute inflammation
Infected open wounds, where heat could worsen the condition
Impaired thermal sensation, as patients may not accurately perceive heat intensity, increasing burn risk
Recent radiotherapy
Severe cardiac abnormalities
Anesthetic areas
Use over reproductive organs
Tuberculosis
Current Standing and Alternatives
Shortwave diathermy’s use has declined in many regions. This is largely due to a lack of robust empirical evidence supporting its efficacy compared to other therapeutic modalities. Some professionals even suggest removing SWD from physiotherapy curricula.
Despite this decline, SWD is still utilized in some areas, and new research explores its potential for various conditions. Studies have investigated its use in treating respiratory symptoms of COVID-19 or post-amputation phantom pain, suggesting potential benefits in specific therapeutic contexts.
When SWD is not used, various alternative therapeutic modalities can achieve similar effects. These include ultrasound therapy, which uses sound waves to reduce pain and swelling, and laser therapy, which stimulates cellular activity. Other options include manual therapy, therapeutic exercise, and superficial heat therapy, such as hot packs, to manage pain and promote circulation.